A hair transplantation procedure typically involves harvesting donor hair grafts from a donor area, for example, the side and back fringe areas, of a patient's scalp, and implanting them in a bald area, or recipient area. In the past, the harvested grafts were relatively large, between 3-5 mm. However, recent donor grafts may be as small as single follicular units. Follicular units (FUs) are naturally-occurring aggregates of one to five closely-spaced hair follicles that are distributed randomly over the surface of the scalp.
The follicular units may be classified, or “typed,” based on the number of hairs in the unit, and identified in shorthand as an “F1” (single hair follicular unit), “F2” (two-hair follicular unit), etc. In some cases of multiple hair follicular units, the hairs may appear to emanate from a single follicle or point in the skin. In other cases, the hairs may exit the skin slightly spaced from one another.
During a hair transplant procedure, certain locations should be avoided for harvesting or implanting hairs. For example, if a doctor already used a site for harvesting or implanting hairs, the doctor may want to avoid using the same site for a subsequent procedure. Tracking devices have a difficult time tracking some of these sites.
A system is needed that may include a database of harvested and implanted sites. A doctor may use the database to plan future harvesting and implantation. The system may track and record site information even when the actual site cannot be seen, because the system can track features around the site, including follicular units, scalp features, or external markers.
A system is also needed that can track moving features. One way of tracking features is detecting their locations on a still by still basis. A system is needed that can improve tracking and does not need to detect feature locations on a still by still basis. Such a system may utilize motion vectors of features or markers to improve tracking.